Laurent Giles 'Jolly Boat' Exeter |
J24 (Sail No. 4239) Dartmouth |
29er GBR 074 Tynemouth |
List classes of boat for sale |
Daggerboard - use of? |
Post Reply | Page <1 3456> |
Author | ||
G.R.F.
Really should get out more Joined: 10 Aug 08 Location: United Kingdom Online Status: Offline Posts: 4028 |
Post Options
Quote Reply
Topic: Daggerboard - use of? Posted: 18 Sep 08 at 10:34pm |
|
Well that's exactly what happens when you gybe a windsurfer with its plate down, you weight the windward rail. I'd heard it works on dinghies, I shall try it a little harder now on the bear off and round the gybe. |
||
Jack Sparrow
Really should get out more Joined: 08 Feb 05 Location: United Kingdom Online Status: Offline Posts: 2965 |
Post Options Quote Reply Posted: 19 Sep 08 at 8:41am | |
redback
Really should get out more Joined: 16 Mar 04 Location: Tunbridge Wells Online Status: Offline Posts: 1502 |
Post Options Quote Reply Posted: 19 Sep 08 at 11:01pm | |
In GP14s and Scorpions (of which I have more experience) the centreboard is moved forward of vertical to give a bit of feel to the rudder which makes it easier to sail upwind in light winds. As soon as the wind fills in the weather helm generated is a bit too much and the board is moved to vertical.
|
||
G.R.F.
Really should get out more Joined: 10 Aug 08 Location: United Kingdom Online Status: Offline Posts: 4028 |
Post Options Quote Reply Posted: 20 Sep 08 at 10:20am | |
So then we're all agreed now are we?
That when the bottom of the foil goes ahead of the top, in 'filled in' wind, it acts in such a way that to continue efficiently it needs to be moved aft..? Yes? So how do we now feel about planing skiffs with fixed foils when the nose is lifted by the Spinnaker and or a wave and that action has the very same effect? Which is the point I was trying to make, and why skiffs in their present incarnation are inefficient and will, like foiling moths, always have a 'speed ceiling' created by that inefficiency amongst others..(Like stern drag or 'tail walking') Interesting looking at things from a windsurfers perspective isn't it? Edited by G.R.F. |
||
redback
Really should get out more Joined: 16 Mar 04 Location: Tunbridge Wells Online Status: Offline Posts: 1502 |
Post Options Quote Reply Posted: 20 Sep 08 at 5:10pm | |
You are right - ideally the board should sweep back and
even better reduce in area but at high speed we'd not want all the turbulence caused by a centreboard case, so we'll have to stick to a dagger. I really must remember to get the board up a bit in a blow it might help reduce that horrible twitchy feeling when we're doing over 15knots. |
||
dopamine
Groupie Joined: 26 Oct 06 Location: Burkina Faso Online Status: Offline Posts: 68 |
Post Options Quote Reply Posted: 20 Sep 08 at 7:04pm | |
But, in my limited experience, the 4k really lifts its nose when the kite powers up. The RS800 sails much flatter and you can sense it wanting to pitchpole you. Looks like the Alto pole is quite high, lifting the bow? |
||
alstorer
Really should get out more Joined: 02 Aug 07 Location: Cambridge Online Status: Offline Posts: 2899 |
Post Options Quote Reply Posted: 20 Sep 08 at 7:54pm | |
There's many trade offs to be had in boat design- that's why the 50knot mark is being chased by windsurfers, wierd solid wing one-tack specials and a massive foiling trimaran.. And whilst the Moth and Cherub types might be able to make use of this perspective, those of us on stricter classes just have to learn to live with what we've got. But yes, interesting. As ever, no definitive answer. |
||
JimC
Really should get out more Joined: 17 May 04 Location: United Kingdom Online Status: Offline Posts: 6649 |
Post Options Quote Reply Posted: 20 Sep 08 at 8:44pm | |
No. Its an over simplification which relates to certain specific circumstances, most especially an over flexible foil.
Oh good grief, here we go again... Skiffs are course racing boats. They're not intended to hit top speed on a limited number of directions only, so amazingly enough they're not as good at it as craft that are... And the fastest course racing boat in the World are probably the solid wing sail C Class Cats, and according to the guys that sail them they struggle to get much past 20 knots... However they sail close to that *all the time* at amazing apparent wind angles... And in some repects, notably speed achieved as a multiples of wind strength, they are some of the most efficient water craft of all... One of the dimmer witted statements you'll hear round the net is that boards aren't very efficient because whilst they can get damn close to 50knots, and will probably get there very soon (possibly beaten by the kiters), they can only do it is shedloads of wind. These folk claim that multihulls which can't handle the shedloads of wind but can do three times wind speed as opposed to not much more than one times are far more efficient than boards. Frankly that's ****, and I suspect you would agree. Now extrapolate the logic... |
||
G.R.F.
Really should get out more Joined: 10 Aug 08 Location: United Kingdom Online Status: Offline Posts: 4028 |
Post Options Quote Reply Posted: 20 Sep 08 at 8:45pm | |
50 knots has been broken this week or it was then they downgraded it
apparently Kites Edited by G.R.F. |
||
Black no sugar
Really should get out more Joined: 04 Dec 04 Location: Somewhere between Brighton and Lancing Online Status: Offline Posts: 3941 |
Post Options Quote Reply Posted: 20 Sep 08 at 8:46pm | |
Yeah but can you take your sandwiches on board?
|
||
Post Reply | Page <1 3456> |
Forum Jump | Forum Permissions You cannot post new topics in this forum You cannot reply to topics in this forum You cannot delete your posts in this forum You cannot edit your posts in this forum You cannot create polls in this forum You cannot vote in polls in this forum |